Snowmobile Fanatics banner

1 - 6 of 6 Posts

·
Registered
Joined
·
104 Posts
Discussion Starter · #1 ·
what is the difference in the big and small blocks? don't really understand is it like a car bigger cyclenders or more cyclenders means big block?
 

·
Registered
Joined
·
343 Posts
The difference is in the design of the head. Also due to the head design, the physical size of the motor is larger even if CID (displacement) is identical.

The best visual example I can think of is Ford 351 windsor which was a small block and a Ford 351 cleveland which was a big block:

Generally you can tell the difference by looking at the valve covers. if they are long, narrow and rectangular, it's a small block. If they are fat squat and irregular shaped, you're looking at a big block.

There are other differences too, for example bore and stroke. A small block generally has a shorter stroke and is thought to rev higher, whereas a big block has a longer stroke with more torque.

There are other disputed difference between a small and a big block. And for the most part, you can simply tell by the displacement. Generally, anything larger than 366 CID is a big block.
 

·
Registered
Joined
·
265 Posts
mr_green said:
The difference is in the design of the head. Also due to the head design, the physical size of the motor is larger even if CID (displacement) is identical.

The best visual example I can think of is Ford 351 windsor which was a small block and a Ford 351 cleveland which was a big block:

Generally you can tell the difference by looking at the valve covers. if they are long, narrow and rectangular, it's a small block. If they are fat squat and irregular shaped, you're looking at a big block.

There are other differences too, for example bore and stroke. A small block generally has a shorter stroke and is thought to rev higher, whereas a big block has a longer stroke with more torque.

There are other disputed difference between a small and a big block. And for the most part, you can simply tell by the displacement. Generally, anything larger than 366 CID is a big block.

umm, 383, 400, 377, i always though it was the size of block it's self and nothing to do with the bore and the stroke. you can make a 427 small block. or a 390 big block
 

·
Registered
Joined
·
343 Posts
we can talk about the "differences" all day long. nobody called them a "big block" or a "small Block" when they were first used in the 50's. it comes down to differences in cylinder spacing, valve design, casting, stroke, ect bolt patterns on the mains. Most people will be satisfied at hearing "under 350 is a small block"

I am not an expert, so I hope somebody else will chime in.
 

·
Registered
Joined
·
538 Posts
Yes there is a difference between a big block and a small block. The blocks are physically different. And "under 350" isnt a small block. The largest CID smallblock I know of is bored and stroked to like 526. And if your talking about sleds, big block = bigger case. But the same still applies like car engines a small block can still have way more displacement than a small CID big block. Any more ?
 

·
Registered
Joined
·
265 Posts
barney said:
Yes there is a difference between a big block and a small block. The blocks are physically different. And "under 350" isnt a small block. The largest CID smallblock I know of is bored and stroked to like 526. And if your talking about sleds, big block = bigger case. But the same still applies like car engines a small block can still have way more displacement than a small CID big block. Any more ?

exactly what i was trying to say!!!! the size of the holes has nothing to do with weather its a big block or small block
 
1 - 6 of 6 Posts
Top